Centrifugal brake for an airplane antenna winch



Jan. 9, 1934. F. BURGHARDT 1,942,534

CENTRIFUGAL BRAKE FOR AN AIRPLANE ANTENNA WINCH Filed April 29, 1930 2Sheets-Sheet 1 INVENTOR FERDINAND BURGHARDT ATTORNEY Jan. 9, 1934. F.BURGHARDT CENTRIFUGAL BRAKE FOR AN AIRPLANE ANTENNA WINCH Filed April29, 1950 2 Sheets-Sheet 2 INVENTOR FERDWAND BURGHARDT ATTORNEY PatentedJan. 9, 1934 CENTRIFUGAL BRAKE FOR AN AIRPLANE ANTENNA WINCH FerdinandBurghardt, Berlin, Germany, assignor to Telefunken Gesellschaft furDrahtlose Telegraphic in. b. H., Berlin, Germany, a corporation ofGermany Application April 29, 1930, Serial No. 448,319, and in GermanyJune 8, 1929 3 Claims.

An airplane antenna consists as a rule of a metal wire (rope) of more orless great length and being at its end weighted by a weight, said wirebeing wound around a winch drum when the 5 same is not in use. Forrendering the aerial operative the winch is unlocked so that on accountof the action of the weight attached at the end of the aerial plus itsdead weight, the aerial becomes unreeled from the drum and thus causesthe winch to revolve; In order that .the unwinding speed may be limited,the winch as a rule is furnished with a centrifugal brake.

When pulling in the aerial this operation should be accomplished veryspeedily and easily (for instance, prior to an emergency landing)without being hindered by the centrifugal brake. With this end in viewit has been suggested in the prior art to interpose between the winchdrum and the axis driving the centrifugal weights of the brake anelement adapted to couple the said two parts only in one direction. Thisfree-wheel clutch (pawls and ratchet, ball slip clutch, etc.) causes thecentrifugal weight brake to rotate only in the sense corresponding tothat of unwinding the antenna, while when winding the antenna up, theaxis of the centrifugal weights is entirely uncoupled or disengaged.

Now, the following invention makes it possible to insure automaticrelease or disengagement of the brake action in dependence upon thedirection of rotation of the winch without the use of a free-wheelclutch.

The invention is based upon the understanding that, in so far as thedisengagement of the brake action is concerned, it is not necessary atall to disengage the centrifugal-weight brake, indeed, that it isentirely suificient to lock the centrifugal weights in the direction ofrotation where braking is undesirable, by the agency of an automaticallyacting locked slide so that they are prevented from flying apart. Aslide of this kind is simpler and cheaper than a free-wheel clutch; itacts with greater reliableness and allows of a compact assembly of winchand retarding device. The said slide most suitably is coupled with thewinch by a convenient transmission gear and it is provided with drive orenergizing means such as a bolt stop claw or the like adapted to entrainthe centrifugal brake in both directions of rotation. The lockerelements may be constructed in this manner that the fly-wheel weightsare provided with suitable pins or bolts, and the slide withcorresponding locker slots in such a way that in the direction ofrotation in which the brake action is to be blocked, the slide becomesso positioned relative to the centrifugal brake that the said pins comevto engage in the locker slots of the slide, so that the fly-wheelweights are thereby locked and prevented from flying apart. In the caseof the opposite direction of rotation, the driver slide is displacedinrelation to the fly-wheel brake so asto assume an unlocking position insuch a way that the pins of the brake come to be positioned opposite theopening of the locker slots so that the fiywheel weights are enabled tofly apart unimpededly as soon as a certain rate of speed has beenattained.

One embodiment of the basic idea of the invention is illustrated in theaccompanying drawing by way of example. Fig. 1 shows a generalarrangement embodying the basic idea partly in section, with omission ofcertain unessential details. The brake depending upon the action offly-wheel weights is accommodated within a stationary casing whereinalso the shaft :c of the antenna winch H is supported. The driver slide0 is supportedinside, the case revolubly about the axis 3, and the sameis furnished with a gear wheel 12 which is in mesh relation with atlarger toothed wheel u keyed upon the winch shaft :0. A bottom view anda perspective view, respectively, of slide 0 is illustrated in Figs. 2and 2a, respectively. To act as a driving means adapted to drive thecentrifugal weights the slide is provided with a bolt m attached to itsextension 76, and as a locking means adapted to lock the fiy-wheelweights with the locker slot 6 with openings The centrifugal-weightbrake is revolvably disposed upon the axis 8 inside the ring-shapedfriction surface fixedly arranged in the casing 9. As' can be seen fromFig. 3 the centrifugal brake comprises a carrier plate a. supported uponthe shaft 8, and two centrifugal weights (brake shoes) b1, b2, flexiblyconnected-39 therewith by the pins 21, i2. Said shoes bl, b2, whenunlocked, are capable of deviating outwardly against the action of thesprings h about their pivots i1, 22 upon a certain rate of speed havingbeen attained, so that by their friction against" 100 the stationaryring surface '1" the desired retarding action is obtained.

Fig. 4 shows a bottom view and Fig. 4a a top view of the co-acting driveslide 0 and the centrifugal-weight brake in unlocked condition. Theassumption is here made that the rotation of the brake in clockwisedirection (looking from below. Fig. 4) corresponds to the unreeling ofthe antenna wire. The bolt m of the slide then engages the side of theopening 01 of the carrier' plate a of the brake and thus causes thecentrifugal brake to revolve. Incidentally the looking bolts d1, d2, ofthe fly-Wheel weights come to be positioned in the openings f, of thelocker slots ,6, e', of slide 0, so that they become unlocked and arecapable of flying freely apart.

In case of contrary direction of rotation the slide occupies a positionin relation to the fly-.

wheel brake which is shown in Fig. 5 looking from below, and Fig. 5alooking from above. The longitudinal axis of the drive slide is turned(see Fig. 5) in relation to the fly-wheel brake from its previousposition AA into position BB in anticlockwise direction. Incidentallythe drive bolt m moves inside the opening 91 until it strikes again anew stopping point whereby the centrifugal brake is entrained again.However, the locking pins d1, (12, have now entered the locker slots ccof the slide and thusprevent the rotating fly-wheel weights fromdeflecting.

In the foregoing description of the brake gear the assumption has beenmade that unwinding :of the antenna corresponds to left-hand rotation ofthe winch or right-hand rotation of the centrifugal brake (see Fig. 4).If, in case of different conditions of mounting, the antenna is to bewound about the winch in the opposite direction so that its unwindingwould correspond to right-hand rotation of the winch, and to lefthandrotation of the fly-wheel brake, it will be understood that thebrake'gear can be readily adapted to this changed condition. -For if thebrake is designed symmetrically in relation to I claim:

1. In signalling apparatus to be used on aircraft, a reel adapted toextend and draw in the signal absorption member comprising a ro tat-abledrum, a gear fixed to said drum, a driven gear meshing with said firstnamed gear, brake means cooperating with said driven gear, and positivemeans for rendering said brake ineans operative when said driven gear isrotated in one direction and for rendering said brake means inoperativewhen rotated in the other direction.

An arrangement as claimed in claim 1 in which said brake means comprisesa member associated with said gear for rotation therewith, a speedretarding member pivoted at one end on said last named member, a rockermember rotatably mounted with respect to said gear, and means on saidrocker member for preventing radial movement of said speed retardingmember when the driven gear is rotated in one direction.

3. In a radio antenna reel comprising a rotatable drum adapted to extendand draw in a signal absorption member, a stationary casing within saiddrum, a pair of shafts within the casing, a first gear fixed to one ofthe shafts, a second gear meshed with the said first gear and movable onthe other shaft, a rocker member having diametrically opposite engaginglugs integral with said second gear, a bolt at right angles to saidslots, a plate having apertures for engaging said bolt, a pair ofcentrifugal brakes arranged to extend outward, a pair of spirally woundsprings holding said brakes in a nonbraking position, and a plurality oflocking studs mounted on said brakes to engage the lugs in said rockermember to place the brakes in a braking position within the stationarycasing when the rotatable .drum is turned in a direction to extend the'signal absorption member.

FERDINAND BURGHARDT.

